A professor of philosophy wanted to teach his class about time management. He stood before his class with some items in front of him. When the class began, wordlessly he picked up a large empty mayonnaise jar and proceeded to fill it with rocks about two inches in diameter. He then asked the students if the jar was full. They agreed that it was full.
So the professor then picked up a box of pebbles and poured them into the jar. He shook the jar lightly and watched as the pebbles rolled into the open areas between the rocks. The professor then asked the students again if the jar was full. They chuckled and agreed that it was indeed full this time.
The professor picked up a box of sand and poured it into the jar. The sand filled the remaining open areas of the jar. “Now,” said the professor, “I want you to recognize that this jar signifies your life. The rocks are the truly important things, such as family, health and relationships. If all else was lost and only the rocks remained, your life would still be meaningful. The pebbles are the other things that matter in your life, such as work or school. The sand signifies the remaining “small stuff” and material possessions.